title: New long circulating magnetoliposomes as contrast agents for detection of ischemia-reperfusion injuries by MRI.
abstract: New long circulating magnetoliposomes coated with polyethylene glycol (PEG), and loaded with PEG-coated 10nm superparamagnetic iron oxide nanoparticles (SPION), were developed. The magnetoliposomes relaxivities r1, r2 measured in a magnetic field of 7 T showed a minor effect on T1, but a major effect on T2. These nanosystems were used as a negative contrast agent for MRI in a nonclinical study to visualize, in a rat model of liver ischemia, ischemia-reperfusion injuries. Magnetic resonance micro-images (MRM) at 7 T were obtained for rat liver with and without magnetoliposomes administration and analyzed in comparison with liver biomarkers and histological results. These new long circulating magnetoliposomes enhanced the detection of lesions indicating their potential use as efficient MRI negative contrast agent for the detection of liver ischemia-reperfusion injuries.
  
  
  BACKGROUND
  This paper describes the generation of PEGylated magnetoliposomes and demonstrates their feasibility as negative contrast agents in a liver ischemia-reperfusion rat model.
authors.affiliation: Intracellular Trafficking Modulation for Advanced Drug Delivery Group, iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal. Electronic address: barbaramartins@ff.ul.pt.
authors.forename: M Bárbara A F
authors.initials: MB
authors.lastname: Martins
authors.affiliation: Intracellular Trafficking Modulation for Advanced Drug Delivery Group, iMed.UL, Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal.
authors.forename: M Luísa
authors.initials: ML
authors.lastname: Corvo
authors.affiliation: Chronic Disease Research Center, Faculdade de Ciências Médicas-Universidade Nova de Lisboa, Campo dos Mártires da Pátria, Lisboa, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Marcelino
authors.affiliation: Departamento de Química e Bioquímica & Centro de Química e Bioquímica-Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal.
authors.forename: H Susana
authors.initials: HS
authors.lastname: Marinho
authors.affiliation: CENIMAT-I3N-Departamento de Ciências dos Materiais - Faculdade de Ciências e Tecnologia-Universidade Nova de Lisboa, Campus da Caparica, Caparica, Portugal.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Feio
authors.affiliation: CENIMAT-I3N-Departamento de Ciências dos Materiais - Faculdade de Ciências e Tecnologia-Universidade Nova de Lisboa, Campus da Caparica, Caparica, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D003287:Contrast Media; D005290:Ferric Compounds / Q000737:chemistry; D006801:Humans; D008081:Liposomes / Q000008:administration & dosage* / Q000737:chemistry; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D018810:Magnetic Resonance Angiography; D058185:Magnetite Nanoparticles / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011859:Radiography; D051381:Rats; D015427:Reperfusion Injury / Q000175:diagnosis* / Q000000981:diagnostic imaging
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D008081:Liposomes; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D011092:Polyethylene Glycols
keywords: Contrast agents; Liver ischemia/reperfusion; Long circulating magnetoliposomes; MRI; SPION